1. Field of the Invention
This invention relates to a high frequency communication connector that is constructed so as to minimize variation in electrical performance when in use.
2. Discussion of the Known Art
Many factors contribute to variations in electrical performance of a high frequency communication connector. For example, dimensional tolerances specified for various parts of the connector, and for the assembly of the parts to one another during production, can combine to produce such performance variations. It is therefore desirable to reduce as much as possible the effects of such manufacturing tolerances, so that operation of the connector is enhanced and a high level of performance is sustained.
There is also a need for a durable, high-frequency communication connector that compensates for (i.e., cancels or reduces) crosstalk among different signal paths through the connector. As defined herein, crosstalk occurs when signals conducted over a first path, e.g., a pair of terminal contact wires associated with a communication connector, are partly transferred by inductive or capacitive coupling into a second path, e.g., another pair of terminal contact wires in the same connector. The transferred signals produce xe2x80x9ccrosstalkxe2x80x9d in the second path, and such crosstalk degrades existing signals routed over the second path.
Applicable industry standards for rating the degree to which communication connectors exhibit crosstalk, do so in terms of near-end crosstalk or xe2x80x9cNEXTxe2x80x9d. These ratings are typically specified for mated plug and jack combinations, wherein input terminals on the plug connector are used as a reference plane. Communication links using unshielded twisted pairs (UTP) of copper wire are now expected to support data rates up to not only 100 MHZ or industry standard xe2x80x9cCategory 5xe2x80x9d performance, but to meet or exceed xe2x80x9cCategory 6xe2x80x9d performance levels which call for at least 46 dB crosstalk loss at 250 MHZ.
U.S. Pat. No. 5,924,896 (Jul. 20, 1999), which is assigned to the assignee of the present invention and application, discloses a high frequency communication jack connector including a printed wire board from which a number of spring contact wires or xe2x80x9cjackwiresxe2x80x9d extend to connect with corresponding terminals of a mating plug connector. Specifically, a rear portion of the wire board is sandwiched between a terminal housing that surrounds and supports two rows of insulation displacement connector (IDC) terminals that are mounted on the top surface of the board, and a lower cover which protects the bottom surface of the board. The cover is joined to a post that extends from beneath the terminal housing and through a corresponding hole in the wire board.
The sub-assembly comprising the joined terminal housing, wire board and lower cover are then fastened as a unit to a jack frame of the connector. Specifically, a front portion of the wire board is inserted in a rear cavity in the jack frame. A latch, which protrudes from the jack frame below the rear cavity, engages a shoulder that is formed at a front edge of the cover below the wire board, thus tending to restrain separation between the jack frame and the sub-assembly in a direction parallel to the wire board.
U.S. Pat. No. 6,116,964 (Sep. 12, 2000), which is also assigned to the assignee of the present invention and application, discloses a communication jack connector having co-planar contact wires that are spaced a certain distance above a wire board. Base portions of the wires are mounted on the board, and certain pairs of the wires have opposed cross-over sections formed near a line of contact between the wires and a mating connector. A coupling region along the wires beyond the cross-over sections compensates for crosstalk introduced by the mating connector. In an arrangement similar to that in the ""896 patent, a sub-assembly is produced wherein a rear portion of the wire board is captured between a terminal housing that surrounds IDC terminals mounted on top of the board, and a lower cover on the bottom surface of the board which is joined to a post extending from the terminal housing. The front of the wire board is inserted in a rear passage in the jack frame, and a latch on the jack frame engages a flange on the lower cover, thus attaching the jack frame and the sub-assembly to one another.
Under certain operating conditions, for example, when outside wire leads are terminated at the IDC terminals within the rear terminal housing, and the leads are dressed inside a wall box or a rack on which the jack frame is mounted, forces may be applied to the connector such as to cause the terminal housing and the wire board to pivot away from the jack frame. Such movement can cause the point of contact between the contact wires of the wire board and the terminals of the plug connector to be displaced from a specified design point, and the electrical performance of the mated connectors will vary accordingly.
A communication connector which can sustain crosstalk compensation meeting Category 6 performance while being subjected to various physical stresses during operation, is therefore very desirable in modern telecommunications environments.
According to the invention, a communication connector includes a connector housing having a front face with a connector opening for receiving a mating connector, and a rear wall. A wire board has a number of contact wires extending above a top surface of the board to establish points of electrical contact with corresponding contact terminals of the mating connector, when the mating connector is received in the opening in the connector housing. A terminal housing is fixed on the top surface of the wire board for supporting associated connector terminals mounted on the wire board, and the terminal housing and the connector housing are constructed and arranged to engage one another when a portion of the wire board and associated contact wires are inserted in the connector housing, thus restraining displacement of the points of electrical contact between the contact wires of the wire board and the contact terminals of the mating connector.
For a better understanding of the invention, reference is made to the following description taken in conjunction with the accompanying drawing and the appended claims.